Neurocognitive is a term used to describe cognitive functions closely linked to the function of particular areas, neural pathways, or cortical networks in the brain. Therefore their understanding is closely linked to the practice of neuropsychology and cognitive neuroscience, two disciplines which broadly seek to understand how the structure and function of the brain relates to thought and behaviour.

A neurocognitive deficit is a reduction or impairment of cognitive function in one of these areas, but particularly when physical changes can be seen to have occurred in the brain, such as after neurological illness, mental illness, drug use or brain injury.